The comparison of two digital numbers in binary format often occurs in digital circuits. For example, in the flag generation circuitry of a first-in first-out (FIFO) memory device described in the above-referenced application, the difference between the write clock pulse counter and a read clock pulse counter is compared to a predetermined number to determine the status of the FIFO.
While in many general purpose computers the comparator circuit is integral with the arithmetic logic unit, in other circuits, such as the comparator circuit described in the preceding paragraph, the comparator circuit performs a single function and, therefore, it is desirable to have a comparator circuit which utilizes a minimum amount of chip area and power supply current.